This invention relates to flexible wiring board pieces to be used in electronic instruments and the like.
This invention also relates to wiring sheets having plural flexible wiring board pieces which are aligned in a separable manner.
Electronic instruments such as hard disk drive units are provided with a so-called head stack assembly consisting of plural so-called head ginbal assemblies, which have magnetic heads at the tip of the gimbals and superposed upon each other, corresponding to plural hard disks in a laminated state. The magnetic heads of the head ginbal assemblies constituting the head stack assembly are each electrically connected to an actuator part having a semiconductor integrated circuit (IC) mounted thereon via a flexible wiring board piece serving as a relay wiring board.
This flexible wiring board piece consists of a plural wiring patterns which are coated with an insulating film except at connecting terminal parts located at both ends.
In the flexible wiring board piece to be used in hard disk drive units as described above, each wiring pattern is extended to form a test pad. After measuring the characteristics of the magnetic head, etc. by using the test pad, the test pad is removed by cutting at one connecting terminal part substantially connected to the actuator part.
In this flexible wiring board piece, it is necessary to prevent the connecting terminal parts exposed outside from being scattered and being short-circuited among the connecting terminal parts, when it is cut at the intermediate part (i.e., the so-called connection-cut terminal part). It is also necessary to prevent a short circuit among the connecting terminal parts caused by the formation of a flash at the cut part.
In addition, it is necessary that a flexible wiring board piece can be easily and stably cut, since it should be cut in a small space.
These flexible wiring board pieces are shipped as such in some cases. Otherwise these pieces are aligned on sheets, shipped in the form of wiring sheets, and then separated by users before using. When processed into wiring sheets, it is therefore desired that these flexible wiring board pieces can be easily separated.
Under these circumstances, the present invention provides flexible wiring board pieces which can be easily cut at the connecting terminal part without causing a short circuit among connecting terminal parts.
The present invention further provides wiring sheets from which flexible wiring board pieces can be easily separated.
A flexible wiring board piece according to the present invention is provided with: at least one circuit wiring pattern made of a conductor foil and having a connecting terminal part; and insulating films formed so as to coat both faces of the circuit wiring pattern and each having a first opening for exposing both faces of the connecting terminal part of the circuit wiring pattern and a second opening for exposing both faces of the cut part of the circuit wiring pattern at a site apart from the first opening.
This invention is regarding the flexible wiring board piece wherein a narrow part for cutting is formed in the cut part of the circuit wiring pattern facing the second opening of the insulating films.
This invention is regarding the flexible wiring board piece wherein the narrow part for cutting is formed in the vicinity of the opening edges of the insulating films.
In the flexible wiring board piece according to the present invention, the connecting terminal part and the cut part are provided in such a manner as being exposed in both faces from openings, which are apart from each other, formed in the insulating films. Thus, the flexible wiring board piece is cut not at the connecting terminal part but at the cut part apart from the connecting terminal part. When the flexible wiring board piece is cut, the free end of the connecting terminal part is coated with the insulating films. Owing to this constitution, connecting terminal parts which are exposed in both faces are not scattered after cutting and thus there arises no short circuit among these connecting terminal parts.
When a narrowing part for cutting is formed in the cut part of a circuit wiring pattern facing one of the openings, the flexible wiring board piece can be easily out by hand.
When this narrow part for cutting is formed in the vicinity of the opening edges of the insulating films, the circuit wiring pattern is cut at the opening edges of the insulating films. In this case, little flash is formed and the circuit wiring pattern scarcely undergoes a short circuit at the cut part after cutting.
A wiring sheet according to the present invention is provided with: a circuit wiring pattern having plural patterns constituting at least one flexible wiring board piece made of a conductor foil and having a connecting terminal part; insulating sheets formed so as to coat both faces of the circuit wiring pattern and having perforations in a part corresponding to the periphery of the flexible wiring board piece; and a plating lead wire for electrically connecting the circuit wiring pattern being exposed on both faces thereof and having a narrow part for cutting in the exposed part.
This invention is regarding the wiring sheet wherein the plating lead wire is formed in the perforated part.
This invention is regarding the wiring sheet wherein the circuit wiring pattern further has a first opening for exposing both faces of the connecting terminal part and a second opening for exposing both faces of the cut part of the circuit wiring pattern at a site apart from the first opening.
This invention is regarding the wiring sheet wherein a narrow part for cutting is formed in the cut part of the circuit wiring pattern facing the second opening of the insulating sheets.
This invention is regarding the wiring sheet wherein the narrow part for cutting is formed in the vicinity of the opening edges of the insulating sheets.
In the wiring sheet according to the present invention, plating lead wires are formed so as to connect aligned adjacent circuit wiring patterns constituting flexible wiring board pieces to each other. Therefore, the desired parts of the circuit wiring patterns of the flexible wiring board pieces can be metal-plated at once in the production process.
In this wiring sheet, a narrow part for cutting is formed in each plating lead wire under exposure and the insulating sheets are perforated in the parts corresponding to the periphery of each flexible wiring board piece. Owing to this constitution, each flexible wiring board piece can be separated from the wiring sheet by hand along the perforations.
By forming a plating lead wire in the perforated part so as to exposed it in both faces, the plating lead wire can be cut along the perforations.